MONDAY, May 4 (HealthDay News) -- With CPR, the more chest compressions the better, a new U.S. study suggests.

Researchers found that when professional rescuers increased the number of compressions during cardiopulmonary resuscitation (CPR), and delayed other interventions to focus on the compressions, the survival rate for people with sudden cardiac arrest doubled.

"Even with professional rescuers, starting IVs and delivering medications can take a back seat to good quality chest compressions," study author Dr. Alex G. Garza, an associate professor of emergency medicine at the Washington Hospital Center and Georgetown University School of Medicine in Washington, D.C., said in a news release from the American Heart Association. "It's a back-to-basics message."

Garza and his research colleagues analyzed the effect of new resuscitation protocols implemented in 2006 by the Kansas City Emergency Medical Services. Under the changes, the highest priority became chest compressions, and rescuers were told to perform 50 chest compressions before pausing to administer two breaths to the patient. Current American Heart Association guidelines for CPR call for 30 compressions followed by two breaths.

The Kansas City EMS also instructed rescuers to delay intubating patients and administering medications to minimize interruptions to chest compressions.

After the changes, overall survival for out-of-hospital cardiac arrest patients increased from 7.5 percent to 13.9 percent. The findings appear in the May 4 online issue of Circulation.

"It takes five to seven chest compressions to raise the pressure enough to begin driving blood into the heart tissue," Garza explained. "If you stop too often to provide a couple of breaths, then you haven't helped the heart much, and you have to start building pressure all over again."

Each year in the United States, EMS workers treat nearly 300,000 people who've suffered sudden cardiac arrest, an abrupt loss of heart function that usually occurs after the heart's electrical impulses become erratic or rapid and prevent effective pumping of blood.

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